Patents by Inventor Jaehyeong Kim

Jaehyeong Kim has filed for patents to protect the following inventions. This listing includes patent applications that are pending as well as patents that have already been granted by the United States Patent and Trademark Office (USPTO).

  • Patent number: 7030693
    Abstract: A method may include determining a power level of a signal and a temperature level of a transmitter originating the signal. At least one of the power and temperature levels may be compared to a lookup table containing predistortion coefficients. The method is capable of predistorting a signal based on the comparison. An apparatus is disclosed in relation to the method.
    Type: Grant
    Filed: April 30, 2003
    Date of Patent: April 18, 2006
    Assignee: Lucent Technologies Inc.
    Inventors: Walter Honcharenko, Jaehyeong Kim, Kyriaki Konstantinou
  • Publication number: 20050182994
    Abstract: A method is provided to accurately predict the probability of successfully recovering frames of (coded) information received over a wireless link, without having to decode the frame. This method, which consists of three steps, requires only limited information about the received signals and the forward error correction code and retransmission scheme being used. First, the signal to noise ratio (SNR) of each of the received signals is measured, where the average SNR is determined for multiple segments that together constitute the frame. Next, an algorithm is employed that takes these SNR values as inputs and determines the so-called effective SNR. The algorithm translates the measured SNR values using an appropriate convex metric, and subsequently combines the resulting values, thereby factoring in the effects of fading, multi-path, and other signal degradations.
    Type: Application
    Filed: February 13, 2004
    Publication date: August 18, 2005
    Inventors: Alexei Ashikhmin, Adriaan Van Wijngaarden, Nandu Gopalakrishnan, Jaehyeong Kim, Emina Soljanin
  • Patent number: 6931080
    Abstract: A predistortion system and method uses an inner predistortion function to adjust a signal being input into a distortion generating circuit and at least one outer predistortion function to adjust the signal being input into the inner predistortion function. Thus, the inner predistortion function can reduce the distortion from the distortion generating circuitry, and any remaining distortion can be reduced by the outer predistortion function.
    Type: Grant
    Filed: August 13, 2001
    Date of Patent: August 16, 2005
    Assignee: Lucent Technologies Inc.
    Inventors: Charles Robert Giardina, Jaehyeong Kim, Haobo Lai
  • Patent number: 6903604
    Abstract: Disclosed is an apparatus and method for modeling and estimating the characteristics of a power amplifier with memory. A predistortion module generates a predistorted signal in response to coefficients of a complex polynomial representative of the amplifier and to an input signal. A power amplifier receives time-spaced samples of the predistorted signal and generates an output signal. A polynomial module updates the coefficients of the complex polynomial in response to a current sample of the output signal and to the time-spaced samples of the predistorted signal. In particular, the complex polynomial is implemented with both even and odd terms.
    Type: Grant
    Filed: June 7, 2001
    Date of Patent: June 7, 2005
    Assignee: Lucent Technologies Inc.
    Inventor: Jaehyeong Kim
  • Publication number: 20040217810
    Abstract: A method may include determining a power level of a signal and a temperature level of a transmitter originating the signal. At least one of the power and temperature levels may be compared to a lookup table containing predistortion coefficients. The method is capable of predistorting a signal based on the comparison. An apparatus is disclosed in relation to the method.
    Type: Application
    Filed: April 30, 2003
    Publication date: November 4, 2004
    Inventors: Walter Honcharenko, Jaehyeong Kim, Kyriaki Konstantinou
  • Patent number: 6794939
    Abstract: A signal is predistorted by producing a first set of sample values using a first predistortion technique, producing a second set of sample values using a second predistortion technique different than the first predistortion technique, and combining the first and second sets of sample values to produce a predistorted signal. At least one of the first and second predistortion techniques produce the corresponding set of sample values based at least in part on a plurality of past time spaced input samples relative to a current time spaced input sample.
    Type: Grant
    Filed: May 31, 2002
    Date of Patent: September 21, 2004
    Assignee: Lucent Technologies Inc.
    Inventors: Jaehyeong Kim, Zhengxiang Ma, Dennis Raymond Morgan
  • Patent number: 6794936
    Abstract: A predistortion system compensates or equalizes the phase and/or amplitude response over frequency of at least a portion of a signal path prior to the distortion generating circuitry, such as an amplifier, and/or of at least a portion of a feedback path after the distortion generating circuitry. For example, in a power amplification system using predistortion, an equalizer on the signal path adjusts the phase and amplitude of a predistorted signal across frequency to compensate for the amplitude and phase response of circuitry on the signal path, such as the amplitude and phase response of analog filters in the up-conversion process. After amplification, an equalizer on a feedback path adjusts the phase and amplitude across frequency of the signal representing the output of the amplifier to compensate for the amplitude and phase response of circuitry, such as analog filters in the down-conversion process, on the feedback path.
    Type: Grant
    Filed: July 3, 2001
    Date of Patent: September 21, 2004
    Assignee: Lucent Technologies Inc.
    Inventors: Liang Hsu, Jaehyeong Kim, Kyriaki Konstantinou
  • Patent number: 6690713
    Abstract: A tracking circuit fine tunes the sampling time to a resolution of ⅛ Tc, where Tc is a chip duration after the searcher circuit finds the timing to within 0.5 Tc. Depending on the prior art tracking circuit that is being used, the input signals are early and late sampled PN despread pilot symbols or early, late and ontime sampled PN despread pilot symbols. Early and late samples are plus or minus one tick or Tt (one tick is ⅛ Tc) away from the ontime samples. The basic principle is that if early and late samples have about the same energy, then the timing is correct. If not, then the sampling time is changed to obtain a balance. In this invention, improved performance of the prior art tracking circuit is obtained by using pilot estimation results, not ontime pilot symbols. In one embodiment, pilot estimation results are low pass filtered signals of ontime symbols which are normally generated upstream of the tracking circuit.
    Type: Grant
    Filed: June 19, 2000
    Date of Patent: February 10, 2004
    Assignee: Lucent Technologies Inc.
    Inventors: Jaehyeong Kim, Steven F Swanchara
  • Publication number: 20030222712
    Abstract: A signal is predistorted by producing a first set of sample values using a first predistortion technique, producing a second set of sample values using a second predistortion technique different than the first predistortion technique, and combining the first and second sets of sample values to produce a predistorted signal. At least one of the first and second predistortion techniques produce the corresponding set of sample values based at least in part on a plurality of past time spaced input samples relative to a current time spaced input sample.
    Type: Application
    Filed: May 31, 2002
    Publication date: December 4, 2003
    Inventors: Jaehyeong Kim, Zhengxiang Ma, Dennis Raymond Morgan
  • Patent number: 6601078
    Abstract: A time-efficient real-time correlator is provided for use in a receiver of a wireless communications system. The correlator correlates a signal received by the receiver with a pseudo-random number (PN) code in order to determine the time delay of the received signal. The correlator requires no memory for storing samples of the received signal. A shift register having only W storage elements is utilized for storing the samples of the PN code sequence, where W is a positive integer corresponding to the length of the correlation window. W+1 correlation results storage elements are utilized to store correlation result values. When the correlator receives a current sample of the incoming signal, the current sample r(j) is multiplied by each of the samples of the PN code sequence to obtain products. The correlation result values stored in the correlation results storage elements are added to the products and the resulting sum is stored in the correlation results storage elements.
    Type: Grant
    Filed: January 27, 2000
    Date of Patent: July 29, 2003
    Assignee: Lucent Technologies Inc.
    Inventors: Miroslaw B. Bondarowicz, Jaehyeong Kim
  • Publication number: 20030086507
    Abstract: A method for softlimiting or clipping a signal. The method includes the step of searching for at least the highest peak above a threshold within a first window created from a set of samples of the signal. Thereafter, a threshold-correcting signal is added to the highest peak found.
    Type: Application
    Filed: November 7, 2001
    Publication date: May 8, 2003
    Inventors: Jaehyeong Kim, Kumud K. Sanwal
  • Publication number: 20030063686
    Abstract: A predistortion system uses a predistortion function which is a combination of functions which are dependent on one of a plurality of time spaced samples of the input signal and independent of the other samples. Using such a structure for the predistortion function enables an easier and low cost implementation. For example, a plurality of time spaced samples are used by predistortion circuitry to produce the predistorted signal. The predistortion circuitry includes first function ciruitry which produces a current sample output value depending on a current input sample and independent of a delayed input sample. A second function produces a delayed sample output value depending on the delayed input sample and independent of the current input sample. Each of any additional functions produces an additional delayed sample output value depending on an additional delayed input sample and independent of any other input samples. The sample output values are combined to produce the predistorted sample.
    Type: Application
    Filed: July 25, 2001
    Publication date: April 3, 2003
    Inventors: Charles Robert Giardina, Jaehyeong Kim, Kyriaki Konstantinou
  • Patent number: 6542756
    Abstract: A method is disclosed for deriving an optimum decision criteria to detect forward link power control bits by a base station from a reverse link signal. In managing the forward link received power, a mobile station commands the base station to incrementally alter the forward link transmit power, by sending periodic power control bits to the base station on a reverse link signal. The transmitted power control bits may be distorted by channel imperfections and multipath effects. The method disclosed derives an optimum decision variable for performing power control bit estimation at the base station. In a preferred embodiment, the optimum decision variable is computed by considering the in-phase and quadrature components of a single power control group received on the reverse pilot channel.
    Type: Grant
    Filed: February 29, 2000
    Date of Patent: April 1, 2003
    Assignee: Lucent Technologies Inc.
    Inventor: Jaehyeong Kim
  • Publication number: 20030042978
    Abstract: A predistortion system compensates or equalizes the phase and/or amplitude response over frequency of at least a portion of a signal path prior to the distortion generating circuitry, such as an amplifier, and/or of at least a portion of a feedback path after the distortion generating circuitry. For example, in a power amplification system using predistortion, an equalizer on the signal path adjusts the phase and amplitude of a predistorted signal across frequency to compensate for the amplitude and phase response of circuitry on the signal path, such as the amplitude and phase response of analog filters in the up-conversion process. After amplification, an equalizer on a feedback path adjusts the phase and amplitude across frequency of the signal representing the output of the amplifier to compensate for the amplitude and phase response of circuitry, such as analog filters in the down-conversion process, on the feedback path.
    Type: Application
    Filed: July 3, 2001
    Publication date: March 6, 2003
    Inventors: Liang Hsu, Jaehyeong Kim, Kyriaki Konstantinou
  • Publication number: 20030031270
    Abstract: A multiple stage and/or nested predistortion system and method uses an inner predistortion function to adjust a signal being input into a distortion generating circuit and at least one outer predistortion function to adjust the signal being input into the inner predistortion function. Thus, the inner predistortion function can reduce the distortion from the distortion generating circuitry, and any remaining distortion can be reduced by the outer predistortion function. For example, in an adaptive predistortion system where the distortion generating circuit is an amplifier, an inner predistortion loop comprises an inner predistortion function which distorts the signal on the main signal path prior to the amplifier. The inner predistortion function can be produced using an output of the inner predistortion function and an output of the amplifier. An outer predistortion loop comprises an outer predistortion function which distorts the input signal prior to the inner predistortion function.
    Type: Application
    Filed: August 13, 2001
    Publication date: February 13, 2003
    Inventors: Charles Robert Giardina, Jaehyeong Kim, Haobo Lai
  • Publication number: 20030020538
    Abstract: Disclosed is an apparatus and method for modeling and estimating the characteristics of a power amplifier. A predistortion module generates a predistorted signal in response to a predistortion function and an input signal. A power amplifier receives the predistorted signal and generates an output signal. A polynomial module generates coefficients of a complex polynomial of order p (p is an integer greater than one) in response to the predistorted signal and the output signal. In particular, the complex polynomial is inplemented with both even and odd terms, thereby improving the ability to accurately model the power amplifier.
    Type: Application
    Filed: June 7, 2001
    Publication date: January 30, 2003
    Inventor: Jaehyeong Kim
  • Patent number: 6504425
    Abstract: Disclosed is an apparatus and method for modeling and estimating the characteristics of a power amplifier. A predistortion module generates a predistorted signal in response to a predistortion function and an input signal. A power amplifier receives the predistorted signal and generates an output signal. A polynomial module generates coefficients of a complex polynomial of order p (p is an integer greater than one) in response to the predistorted signal and the output signal. In particular, the complex polynomial is implemented with both even and odd terms, thereby improving the ability to accurately model the power amplifier.
    Type: Grant
    Filed: June 7, 2001
    Date of Patent: January 7, 2003
    Assignee: Lucent Technologies Inc.
    Inventor: Jaehyeong Kim
  • Patent number: 6498529
    Abstract: Disclosed is an apparatus and method for iteratively calculating the predistortion function from a power amplifier when the inverse to the power amplifier characterization does not exist analytically. A predistortion module generates a predistorted signal in response to an input signal and a predistortion function received from a predistortion function calculating module. The predistortion function calculating module generates the predistortion function in response to given amplifier characteristics. In particular, the predistortion function calculating module uses a magnitude of the input signal at a given time to estimate the predistorted signal at that given time in order to calculate the predistortion function. Optionally, subsequent iterations based on the magnitude of the estimate occur until a desired accuracy of the predistorted signal approximation and of the predistortion function is achieved.
    Type: Grant
    Filed: June 8, 2001
    Date of Patent: December 24, 2002
    Assignee: Lucent Technologies Inc.
    Inventors: Jaehyeong Kim, Kyriaki Konstantinou
  • Publication number: 20020190787
    Abstract: Disclosed is an apparatus and method for iteratively calculating the predistortion function from a power amplifier when the inverse to the power amplifier characterization does not exist analytically. A predistortion module generates a predistorted signal in response to an input signal and a predistortion function received from a predistortion function calculating module. The predistortion function calculating module generates the predistortion function in response to given amplifier characteristics. In particular, the predistortion function calculating module uses a magnitude of the input signal at a given time to estimate the predistorted signal at that given time in order to calculate the predistortion function. Optionally, subsequent iterations based on the magnitude of the estimate occur until a desired accuracy of the predistorted signal approximation and of the predistortion function is achieved.
    Type: Application
    Filed: June 8, 2001
    Publication date: December 19, 2002
    Inventors: Jaehyeong Kim, Kyriaki Konstantinou
  • Publication number: 20020193087
    Abstract: Disclosed is an apparatus and method for modeling and estimating the characteristics of a power amplifier with memory. A predistortion module generates a predistorted signal in response to coefficients of a complex polynomial representative of the amplifier and to an input signal. A power amplifier receives time-spaced samples of the predistorted signal and generates an output signal. A polynomial module updates the coefficients of the complex polynomial in response to a current sample of the output signal and to the time-spaced samples of the predistorted signal. In particular, the complex polynomial is implemented with both even and odd terms.
    Type: Application
    Filed: June 7, 2001
    Publication date: December 19, 2002
    Inventor: Jaehyeong Kim